In large signs, used as scoreboards and television picture reproduction display media, color production depends upon programmable control of, for example, three primary-colored light sources within each color module or pixel of the display. The effective contribution of each of the three light sources of each pixel is determined either by controlling the intensity of light emitted or by controlling the periodic "ON" time of each light source within the pixel. Each pixel thus provides a mix of colored light by which a wide spectrum of color for each module of the sign is produced. In small signs, light-emitting diodes (LEDs) are available in actual or near prime colors. In larger signs, requiring greater light emission than is available from LEDs, display construction depends upon larger light sources such as filament based lights. In this latter case, the generation of basic primary colors usually has depended upon coating the enclosure of the light source or adding an exterior color producing filter.
It is expensive, and often prohibitively so, to acquire and maintain inventory for maintenance of lamps for a large display which are variously permanently colored using colored glass or the like for the lamp enclosures. Use of currently known and available lamp enclosure coatings has also proved unsatisfactory due to inability to withstand weathering and heat from the lamps. Such coatings not only are unsatisfactory due to reduction of the lamp's useful life, but also add to the inventory cost as such coatings cannot be added or changed at remote sign sites. Until now, no low cost, long lasting, integumental color filter cover for a large variety of large display lamp colorations has been proposed.